2 files changed, 38 insertions, 10 deletions

diff --git a/snug-clean/src/Snug/Compile/Simulate.dcl b/snug-clean/src/Snug/Compile/Simulate.dcl
index a36dc0d..bf01675 100644
--- a/snug-clean/src/Snug/Compile/Simulate.dcl
+++ b/snug-clean/src/Snug/Compile/Simulate.dcl
@@ -9,14 +9,24 @@ from Control.Monad.State import :: State, :: StateT,
 	instance pure (StateT s m), instance <*> (StateT s m)
 from Data.Functor import class Functor
 
-from MIPS.MIPS32 import :: Instruction, :: Label
+from MIPS.MIPS32 import :: Immediate, :: Instruction, :: Label, :: Offset,
+	:: Register
 from Snug.Syntax import :: BasicValue
 
 :: Simulator a :== State SimulationState a
 
 :: SimulationState
 
-simulate :: !(Simulator a) -> [Instruction]
+:: StackValue
+	= SVIndirect !Offset !Register //* value stored in reg + offset
+	| SVRegOffset !Register !Offset //* value is reg + offset
+
+	/* for internal use only: */
+	| SVImmediate !Immediate
+
+simulate :: ![StackValue] !(Simulator a) -> [Instruction]
+
+stackSize :: Simulator Int
 
 //* Build a constructor node with *n* arguments and push it to the stack.
 buildCons :: !Label !Int -> Simulator ()
@@ -27,6 +37,13 @@ buildThunk :: !Label !Int -> Simulator ()
 pushBasicValue :: !BasicValue -> Simulator ()
 
 /**
+ * Push the *j*th argument of the *i*th element on the stack onto the stack.
+ * @param *i*
+ * @param *j*
+ */
+pushArg :: !Int !Int -> Simulator ()
+
+/**
  * Overwrite the node currently under evaluation with an indirection to the
  * node on top of the stack, and continue evaluating that node instead.
  */
diff --git a/snug-clean/src/Snug/Compile/Simulate.icl b/snug-clean/src/Snug/Compile/Simulate.icl
index b383936..672b47e 100644
--- a/snug-clean/src/Snug/Compile/Simulate.icl
+++ b/snug-clean/src/Snug/Compile/Simulate.icl
@@ -17,22 +17,20 @@ import Snug.Syntax
 	, stack     :: ![StackValue]
 	}
 
-:: StackValue
-	= SVImmediate !Immediate
-	| SVRegOffset !Register !Offset /* value is reg + offset */
-
-simulate :: !(Simulator a) -> [Instruction]
-simulate sim = flatten (reverse (execState sim initial).instrs)
+simulate :: ![StackValue] !(Simulator a) -> [Instruction]
+simulate stack sim = flatten (reverse (execState sim initial).instrs)
 where
 	// TODO: when finishing:
 	// - check that the stack is empty
-	// - update heap pointer
 	initial =
 		{ instrs = []
 		, hp_offset = 0
-		, stack = []
+		, stack = stack
 		}
 
+stackSize :: Simulator Int
+stackSize = gets \s -> length s.stack
+
 add :: ![Instruction] -> Simulator ()
 add is = modify \s -> {s & instrs=[is:s.instrs]}
 
@@ -80,6 +78,10 @@ storeStackValue (SVRegOffset reg offset) doffset dreg = add
 	[ AddImmediate Signed TempImm reg (Immediate offset)
 	, StoreWord TempImm doffset dreg
 	]
+storeStackValue (SVIndirect offset reg) doffset dreg = add
+	[ LoadWord TempImm offset reg
+	, StoreWord TempImm doffset dreg
+	]
 
 buildCons :: !Label !Int -> Simulator ()
 buildCons cons nargs =
@@ -104,6 +106,15 @@ where
 		BVInt i -> i
 		BVChar c -> toInt c
 
+pushArg :: !Int !Int -> Simulator ()
+pushArg i j =
+	getState >>= \{stack} ->
+	case stack !! i of
+		SVRegOffset reg offset ->
+			push (SVIndirect (offset + (j+1)*4) reg)
+		_ ->
+			abort "unexpected reference in pushArg\n"
+
 indirectAndEval :: Simulator ()
 indirectAndEval =
 	pop >>= \sv ->